I about 6 months ago I was researching RadonSeal also. I was never able to find any unbiased testimonials to say whether it worked or not, so I decided to play it save and not use it. I decided to use UGL Drylock instead.
I am curious what you, SFM, ended up doing? Did you try RadonSeal? If so, I'd love to hear your results.

Craftsman,
I was looking at UGL, RadonSeal, and Sani-Tred....haven't heard much of anything on any of them...just curious how your UGL worked...how extensive was your leakage...what type of application was it.

Thanks

Consumer reports says that UGL DryLok is the best for water sealer according to there tests.